Method of removing alkali metal contamination from a gaseous stream

Abstract

A method is described for effecting the removal of alkali metal contaminants from a super heated gaseous mixture useful in power generation. Finely divided refractory oxide particles are introduced into the hot gaseous mixture without effecting a substantial reduction in the temperature and operating efficiency of the system. The alkali metal contaminants are substantially removed from the hot gaseous mixture by being adsorbed onto the surface of the finely divided refractory oxide particles.

What we claim as new and desire to secure by Letters Patent of the United States is: 
     
       1. A method of removing alkali metal compounds from a gaseous mixture superheated to a temperature suitable for power generation which contains such alkali metal compounds in vaporous form comprising, (1) introducing into the superheated gaseous mixture finely divided refractory oxide particles having an average diameter of from 0.005 micron to 1 micron which are utilized in an amount sufficient to provide a total adsorption surface area sufficient to reduce the level of alkali metal contamination of the superheated gaseous mixture to an acceptable value prior to the introduction of the superheated gaseous mixture into the gas turbine,   (2) introducing the resulting heated gaseous mixture into the gas turbine at a flow rate sufficient to energize the gas turbine,   (3) exhausting the resulting gaseous mixture into a precipitator to effect particle removal, and   (4) thereafter venting the resulting gases substantially free of refractory oxide particles into the atmosphere.   
     
     
       2. A method in accordance with claim 1, where the finely divided metal oxide particles are finely divided aluminum oxide. 
     
     
       3. A method in accordance with claim 1, where the finely divided refractory oxide particles are finely divided silicon dioxide. 
     
     
       4. A method in accordance with claim 1, where the refractory oxide particles are in the form of a mixture of alumina and silicon oxide. 
     
     
       5. A method in accordance with claim 1, where the refractory oxide particles are in the form of finely divided titanium oxide. 
     
     
       6. A method in accordance with claim 1, where the refractory oxide particles are in the form of finely divided iron oxide. 
     
     
       7. A method in accordance with claim 1, where the refractory oxide particles are in the form of finely divided zirconium oxide. 
     
     
       8. A method in accordance with claim 1, where the superheated gaseous mixture originates in a pressurized fluid bed coal reactor. 
     
     
       9. A method in accordance with claim 1, where the finely divided refractory oxide particles are generated in a flame reactor resulting from the combustion of a metal or metalloid chloride. 
     
     
       10. A method in accordance with claim 1, where the finely divided refractory oxide is generated in a plasma reactor resulting from the combustion of a metal or metalloid chloride. 
     
     
       11. A method in accordance with claim 1, where the finely divided refractory oxide is generated in a reactor based on the combustion of a metal or metalloid chloride at a temperature of at least 1700° F.